Control apparatus for oil burners



M 1941- J. R. HAWLEY 2,255,318

CONTROL APPARATUS FOR OIL BURNERS Filed Aug. 21, 1939 2 Sheets-Sheet l It I as A 3 I I I l L-u-l K l l J 1 z/ I I 3/ L20 Pi 4 IIII'I ".ualll IINVENTOR JAMES HAM/45V Q ATTORNEY INVENTOR JAMES A? HA MEV 2Sheets-Sheet 2 J. R. HAWLEY CONTROL APPARATUS FOR OIL BURNERS Filed Aug.21, 1939 Sept. 9, 1941.

ATTORNEY Patented Sept. 9, 1941 CONTROL APPARATUS FOR OIL BURNERS JamesR. Hawley, Seattle, Wash, assignor to Mechanical Products ManufacturingCompany, '(not incorporated), Seattle, Wash.

Application August 21, 1939, Serial No. 291,148

9 Claims.

This invention relates to heating systems and more particularly toimprovements in oil burners designed for the heating of homes, forcommercial plants and various other uses, and adapted to burn what isgenerally referred to as heavy fuel oil; it being the principal objectof this invention to adapt the principle of atomization of heavy fueloils, by applying heat and mechanical pressure to small capacitynozzles, thereby to render their operation satisfactory and free fromcoking or other fouling.

Explanatory to the invention, it will be here stated that it has beenrecognized in the use of heavy fuel oils that a greater heatingefiicicncy can be obtained in the burning operation if the temperatureof the fuel oil is raised to a degree near the temperature of combustionbefore it is atomized for ignition in the combustion chamber.

In some burners, provision has been made for such heating of the oil,but usually at some point remote from the actual point of atomizationand burning.

There have been some disadvantages observed in such preheating of theoil at a point distant from the point of combustion; for example, in theresultant heat loss from the oil as it flows from the point of heatingto the point of combustion, and the corresponding loss of burningefficiency. It has been particularly noted, however, that should thepre-heating be carried to a high degree suflicient to compensate forthis drop in efiiciency due to heat loss, there will then be theobjectionable feature of coking of the oil in the preheating coils andapparatus, requiring that they be periodically cleaned of such coke orcarbon, or that the apparatus ultimately be replaced because ofresultant deterioration.

Furthermore, small particles of this coke will be dislodged from theinside walls of the heater pipes, and will be carried to the atomizingnozzle, either partially or completely closing the orifice therein,rendering the burner inoperable and also presenting a serious hazard tosafety. It is also possible that such particles of carbon or coke wouldclog or foul the valve plunger in its valve seat, holding it partiallyopen, and allowing a slow drip or leaking of the oil, also creating aserious hazard to safety.

Another disadvantage incident to the preheating of the oil at a pointremote from the point of ignition, is due to the long period of timerequired to bring the oil to a temperature for ignition.

In view of the above mentioned, and other disadvantages in systems asgenerally manufactured,

it has been an object to provide an oil burner 55 wherein the oil,delivered from a point remote from the burner, is preheated within theburner itself to a degree reasonably close to its vaporizationtemperature, and at a point substantially adjacent that where it isdelivered in an atomized condition into the combustion chamber to avoidthe previously mentioned heat loss, nozzle fouling and coking of thepipes.

It is also an object of this invention to provide a burner that willbring about a reduction in the cost of operation by reducing the amountof heat required to efiect proper atomization of the oil and bypreventing overheating of the oil supply.

Still another object of the invention is to provide an oil burnerwherein the time required for the preheating operation prior to startingthe burner is reduced to a minimum.

Another object of the invention is to provide a substantially accuratemeans of controlling the temperature of the oil in the pre-heating tubeor chamber adjacent to the point of atomization so as to preventoverheating of the oil.

A further object of the invention is to provide that, upon shutting offthe burner, the oil temperature in the heating tube or chamber bereduced, thereby dissipating the heat in the coils and eliminating theundesirable results that are incident to allowing over-heated oil tostand in the heating coils.

A still further object of the invention is to provide an oil burner ofthe kind stated, that is relatively simple in construction andrelatively inexpensive to manufacture, that is durable in use, reliableand efiicient in its operation, and otherwise well adapted for itsintended uses.

Other objects of the invention reside in the details of construction ofparts, in their combination and mode of operation as will hereinafter befully described.

In accomplishing these objects, I have provided the improved details ofconstruction, the pre ferred forms of which are illustrated in theaccompanying drawings, wherein- Fig. l is a horizontal, sectional view,taken centrally of a burner embodied by the present invention.

Fig. 2 is a vertical sectional view taken substantially axially of theblast tube of the burner.

Fig. 3 is an enlarged, sectional detail, showing the solenoid actuatedvalve mechanism for controlling oil delivery to the burner nozzle.

Fig. 4 is an enlarged, sectional detail of the burner nozzle and valvemechanism.

Fig. 5 is a wiring diagram, illustrating one way in which the burner maybe wired with electrical controls for automatic operation.

Briefly described, the present burner comprises a housing that containsa fan which is driven by an electric motor for the forcible delivery ofair through a blast tube into the combustion chamber of the stove orfurnace. Located coaxially within the blast tube is an electricallyheated oil delivery tube which, at its outer end is connected to asource of oil supply and at its inner end is equipped with an atomizingnozzle for the derivery of the oil, in an atomized condition with theair blast, into the combustion chamber.

Automatic devices control the energizing of the electrical heatingelement, and also the delivery of oil to the atomizer in accordance withthe obiects oi the invention as previously stated. The automatic meansincludes the usual room thermostat, that may be set to operate at aselected room temperature, a time delay switch for setting the pump andmotor in operation after a predetermined time interval necessary for theoil heating and various relays later to be explained in detail.

Referring more in detail to the drawings- The present device, in apreferred form of con struction, comprises a rectangular base section lwhich mounts thereon a fan housing or casing H. The base member may bemade in various sizes, and of various heights, to best adapt it for usewith stoves, furnaces or boilers of different kinds, and it is equippedwithin its fourcorner portions with vertical legs Illa, with feet lb,and these legs are threaded through mounting brackets I00 fixed in thebase, and they may be vertically adjusted therein to level the burnerand maintain it at a set position.

The fan housing II rests upon and is rigidly fixed to the base memberII). It is substantially rectangular in cross section and within itsupper portion containing an air delivery fan l4. The fan I4 is of thesquirrel cage type and has a hollow hub portion l4a whereby it ismounted upon the end of the drive shaft 15a of an electric motor i5which, in turn, is fixedly mounted upon a side wall of the housing ll.Air enters the fan housing through a side wall opening Ha: opposite themotor.

Mounted on the side wall of the housing ll, about the wall opening llx,is a bracket l9, and supported by the bracket I9 is a fuel oil pumpequipped with a drive shaft i 8a having a driving connection with thedrive shaft of the electric motor l5.

Fixed to the pump housing is an oil filtering device, designated in itsentirety by numeral 20, and this is connected by a pipe 2| with a sourceof supply of fuel oil, not shown. Upon operation of the pump, oil willbe drawn through pipe 2| to the filter, and then delivered therefromunder pressure, to the oil heating tube, later to be de scribed.

The lower portion of the fan housing H is rectangular in cross section,and is slightly larger than the upper portion, converging at its forwardside to a cylindrical neck lib from which a cylindrical air blast tubeI3 extends for directing the air supplied by the fan l4 to thecombustion chamber of the furnace with which the burner is used. At itsdelivery end, the tube is fitted with a nozzle member l3 forconcentrating the blast and this may, if desired, be equipped with finsor deflectors, not shown, for causing a whirling or swirling delivery ofthe mixture into the combustion chamber.

Disposed horizontally within the housing H and coaxially of the blasttube I2 is the oil heating tube 25. The rearward end of this tubeextends through the rearward wall of the housing ll and is thereprovided with a tubular fitting 26 to which an oil delivery tube 21 fromthe pump I8 connects for supplying oil to the heating tube. At itsforward end, the tube 25 is equipped with an atomizing tip 28 and thisis disposed, as noted in Fig. 2, just within and centrally of thedelivery end of the blast tube.

Mounted on a side wall of the housing H, below the motor I5, is atransformer 22, and extending from this are circuit wires 33 and 24leading into the housing and along the tube 25, terminating in ignitionpoints 25 and 36 located adjacent the atomizing nozzle and between whichpoints a spark may be caused to jump for igniting the combustiblemixture as is the usual procedure.

' Mounted upon the fitting 26 and disposed vertically thereon, is asolenoid 30 designed for control and operation of an oil delivery valvewithin the delivery end of tube 25, as presently will be explained.

As seen in Fig. 3, the solenoid 30 comprises a coil 30' that is enclosedwithin a housing 28, and is disposed about a cylindrical, liquid-tight,tubular dome 40, which is threaded into the fitting 26. I'he dome 40contains a steel block 4| which operates as a solenoid core, and, ashere shown, will be drawn upwardly upon energization of the coil.

A link 42 is pivotally connected to the lower end of the core, as at 43,and at its lower end, the link is pivotally attached, as at 44, to alever 45 used in control of the oil valve in the tube, as presently willbe explained.

The tube 25, as noted in Fig. 3, is threaded into a nipple 46 which isfixed to the fitting 26 by a coupling union 41. A tubular fitting 48, isinserted in the fitting 4S and is held in place by the nipple 46 and theunion 41. This fitting 48 is shouldered to limit its insertion in part26 and forms a leak-tight connection with the nipple 46 and it-coaxiallycontains a rod 50, slidable therein within a coaxial bore 5|. It will benoted that the fitting 48 is slotted at its inner end within part 26, asat 52, to receive the end of the lever 45, and this lever 45 ispivotally mounted in the slot 52 by a pin 53. Also, it will be notedthat the rearward end of the rod 50 is slotted as at 54, and receivesthe pivoted end portion of the lever 45. Also, it is seen that a pin 55is fixed. in the rod 50 and extends through the slot, and that a notchor recess 56in the lower edge of the lever receives the pin 55 therein.Ports 5'! in the fitting 48 open into an enlarged central bore 58 for anunrestricted passage of oil therethrough to tube 25.

With this arrangement of parts, energization of the solenoid 30 causesan actuation of the lever 45 whereby the rod 50 will be pulledoutwardly.

Disposed lengthwise within the tube 25 is a filler or spacer tube 50,provided at opposite ends with closure fittings 6l-6l' which seal thetube liquid-tight. These closure fittings 6| are provided with outer endportions 52-62' of a diameter slightly greater than that of tube 60, andthey have an easy sliding fit within the tube 25. These enlargedportions 62-82 are provided with a plurality of notches or grooves 63-63to allow a free and unrestricted passage of oil therethrough and aboutthe tube 60. Furthermore, the closures at the outer end of the tube 60are counterbored, as at 65-45 from the outer end, to a diameter anddepth suitable to loosely receive an end portion of the rod 50, and thevalve plunger, as will presently be explained, which are fixed thereinby pins 66-66 in a. free or flexible connection.

The narrow passage between this filler or spacer tube 60 and the outertube 25 provides for quicker and easier application of heat to the oilflowing therebetween, and these tubes, due to their construction,preferably copper, conduct the heat to the oil very readily. It isobvious that the oil may be heated quicker, more economically, and moreuniformly in this manner.

Referring to Fig. 4, it will be seen that there is a sleeve tightlypressed into the outer end of tube 25, and the tube is threaded into acap II, into which cap an atomizer spray tip or nozzle 28 is threaded.Flow of oil to the atomizer or nozzle 28 is under control of-a valvedevice that is located in the forward end of the tube 25, within the capII and adjacent to the spray tip 28.

The valve device comprises a valve seat member I5 which is threaded in aliquid-tight joint, into an inner end opening provided in the spray tip28. A valve stem or plunger I6 has an outer end portion slidablycontained in a counterbore within an inwardly extending portion of thevalve seat member and has its other end portion loosely contained withinthe counterbore 65 within the closure fitting 6| at that end of thespacer tube 60. A pivot pin 66' connects the parts 16 and 61 in a freeor flexible manner. The valve stem or plunger I6 has a tapered forwardend portion 16a adapted to close against a valve seat formed by atapered bore a in the valve seat I6 to cut off the oil flow through thepart I6 to the atomizing nozzle. It will be understood that uponenergization of the solenoid, the core 4| will be lifted, and the lever45 will be actuated to pull the tube 60 outwardly, thus to unseat thevalve plug from seat I5. Also, upon de-energization of the solenoid, thecore 4| will drop. and this action will move the valve to its closedposition. Flow of oil to the nozzle through fitting I5 is permitted byreason of a plural ty of ports 15b in the inner end portion inside thevalve seat, as noted in Fig. 4. A screen 153 is wrapped about the memberto catch any foreign matter that might be apt to clog the valve ornozzle, or prevent the valve from seating.

A thermostat bulb, designated by reference numeral 80, is disposedagainst the tube 25 near its forward end, and within a shallow,longitudinal groove 8|. This bulb is covered by thin, formed shell 62. Asmall tube 83 leads from the bulb 80 to transmit pressure of expandablemedium used in the bulb to a cut-out switch 84 to provide for control ofthe latter, as will be expla ned in connection with the wiring diagramillustrated in Fig. 5.

A heating coil or element 85 of resistance wire is formed about the tube25, being electrically insulated therefrom by a sheet of suitablematerial, such as sheet mica, or the like, as indicated at 86, and asubstantially thick covering 81, such as plastic asbestos or the like,is applied to the tube 25 and over the element 85, functioning both asan insulation for the said element and as a means of confining the heatof the element to the tube 25, thereby obtaining the maximum efiiciencyfrom the heating element in heating the oil within the tube.

It will be noted that there is a circuit wire 88 leading to the forwardend of the heating coil, and this is embedded in the asbestos cover 81;the other circuit wire 89 connects to the rearward end of the coil;current being supplied, as presently described.

It will be stated that a much lower voltage is here desirable to operatethe relay switch through the room thermostat, and to close the relay inthe stack switch, than is necessary to operate the motor, ignition,heater and valve solenoid; therefore, two sources of current or circuitsare utilized in the present instance.

In the wiring diagram shown in Fig. 5, 90 and 9| designate power linesleading from a source of low voltage current, while 92 and 93 designatepower lines supplying high voltage current. The electric motor I5 hasone side connected by a line 94 with line 93 and its other sideconnected by a line 95 with a contact 96 on the stack switch 91. Thetransformer 32 has one side connected by a wire 98 with the circuit line93 and its other side connected by a wire 99 with a contact I00 of thestack switch 9'1. The switch 9! has a switch arm connected by a line |0|with line 92, and this arm comprises parts I02 and I03 adapted to openor close as a unit, and on closing to engage the contacts 96 and I00,and simultaneously close the high voltage circuit through motor I5 andthe transformer 32. The switch members I02 and I03 are operable toclosed position under control of a solenoid I05 having a circuitconnection I06 with line 90 and a connection I01 through a time delayswitch I08 and wire I09 from the switch to the line 9|. The solenoid I05is energized upon closing of switch I08 which will electrically connectwires I01 and I09.

The room thermostat, which is generally the instrument under whichautomatic control of the burner is placed, is designated at II 0 andthis has one side connected by a line III with circuit line 9| and itsother side connected through a wire 42 to a solenoid coil 3, and thenthrough a wire N20. to a lockout switch H4 and has a wire |I5 connectingwith the line 90.

The time delay switch I08 includes a heating element I20 which functionswhen current is passed therethrough, to heat a bi-metal strip to effectthe closing of switch I08 and thus connect the lines I01 and I09, andenergize the solenoid coil I 05 in the stack switch 91. This solenoidcoil I05 upon being energized closes the switch elements I02 and I03 inthe stack switch, to energize the ignition transformer 32, andsimultaneously operate the valve solenoid 30, and start the motor I5, Itis shown in Fig. 5 that the valve solenoid 30 has a connection I2| withline 93 and a connection I22 with line 95. It is contemplated that theignition transformer 32 and its circuit may be of the intermittentoperation type as well as the continuous operation type; it beingunderstood that the operation of the stack switch 91 is to open thecircuit to the ignition transformer upon the establishment of combustionof the fuel oil through the expansion of a spiral bimetal coil 91a bythe heat of combustion. Furthermore, in case of flame failure, for anyreason, the lookout switch I|4 will be opened and the entire system willclose down automatically. In such cases the stack switch is manuallyrest, by closing the lockout switch H4. This is the conventionaloperation of most standard stack switches now on the market, as is wellknown in the art, but for a better understanding of the operation of thesystem, it might be well to state here that the opening of the lockoutswitch H4 is accomplished by a bi-metal strip which is heated by aheating element connected in the stack switch which will open thelookout switch II4 a short predetermined interval of time after theclosing of the switches I82 and I88 if the spiral bi-metal element 81ais not ail'ected by the heat of combustion.

In heating a home, when the room temperature falls below that for whichthe room thermostat III) is set, the switch IIIIa. therein is closed,thereby energizing the solenoid coil I I5 in the relay I24, which causesthe closing of the switches I25 and I25. These latter switches close thecircuit to the burner thermostatic switch 84 through the lines I28 andI88, and to the time delay relay switch through the lines I82 and I88.

The oil heating element 85 has its ends connected to the burnerthermostatic switch 84 by the wires 88 and 89, and the circuit iscompleted through the normally closed switches 84a and 84b, to energizethe heating element. Upon the heating element 85, the heater tube 25 andthe oil contained therein reaching a certain predetermined temperature,the thermostat bulb 88 operates through the tube 88 to open the switches84a and 84b in the thermostatic switch 84, and when these parts fallbelow a certain predetermined temperature, the thermostat bulb 88operates to close the switches 84a and 84b, thereby maintaining the oilat a substantially constant temperature.

Simultaneously with the energization of the oil heater element 85, thetime delay relay heater element I28 is energized, and after apredetermined period of time, which has been found to be approximatelytwo minutes for most moderate climates, the switch I88 is actuated to aclosed position, thereby closing the circuit to the solenoid coil I85 inthe stack switch. During this period of time, the heater element 85 isheating the oil in the tube 25 to the point where atomization forcombustion is most readily established and maintained most eflicientlyand economically. This period of time, of course, may vary in some casesand then it is necessary to make adjustments in the operation of thetime delay relay, and also in the adjustable burner ther mostatic switch84.

When the solenoid I85 in the stack switch 81 is energized, it operatesto close the switches I82 and I08. Upon these switches I02 and I83 beingclosed, the circuits are closed both to the valve operating solenoid 88,thereby opening the valve, and-to the motor I5, starting the motor whichdrives the fan II and the pump 20, thereby delivering fuel oil underpressure through pipe 25 and a blast of air through tube I3 to supportcombustion, and also at the same time furnishing current to the ignitiontransformer 32, for effecting ignition oi the fuel mixture.

If, for any reason, the ignition should fail, and there occurs what istermed a flame failure, the lock-out switch will operate to close downthe entire electrical circuit, as previously stated.

Upon combustion being established, it will continue, the burneroperating until one of the controls automatically calls for a shut-down.The heating element 85 will remain energized to heat the oil to apredetermined temperature, or will be turned oil. and on intermittentlyto maintain a substantially constant heat under control of thethermostat bulb l8 and the switch 54.

In normal operation, when the room thermostat IIII is satisfied, theswitch IIlla is opened, thereby de-energizing the solenoid coil III foropening the switches I25 and I25 in the relay I24. This opens thecircuit to the heater 55, and the time delay relay element I28. However,a feature of this construction resides in the fact that the time delayrelay switch III will not open for a predetermined interval of time,thereby maintaining the operation of the motor I5, the pump 28, andholding the valve solenoid energized until the circuit is opened. Thisallows the burner to scavenge itself of hot oil in the heater tube 25,and dissipate the heat of the tube itself, in that the burner willcontinue to operate until the time delay relay switch I05 is opened.This provides that the oil temperature in tube 25 be reduced, and thatthe tube itself will be cooled to a safe temperature below which cokingof the oil therein will not take place.

The primary control switch has been described as a room thermostat IIII,operated by air temperature, but it may be replaced by a switch operatedby water temperature or steam pressure, such as in commercialapplications 01' the oil burner, or in a plurality of them, rather thanin a home installation, as herein described. It

is thought obvious that with an oil burner in accordance with theinvention as herein disclosed and described, all of the faults ofpreviously used burners are eliminated.

It is not intended that the claims be limited to the details ofconstruction of parts, but that they be given an interpretationcommensurate with the spirit and scope of the invention disclosed.

Having thus described my invention what I claim as new therein anddesire to secure by Letters Patent is:

1. In an oil burner an oil delivery tube equipped with an atomizingnozzle at its delivery end, a valve in the tube for controlling the flowof oil therefrom to the nozzle, an electric heating element associatedwith the tube for heating the oil contained therein, an electric circuitfor the heating element including a cut-out switch, a device adapted tobe electrically energized to open the control valve, an electricallyenergized time delay switch operable to energize said device after apredetermined time interval with reference to energization of the timedelay switch, and a control switch common to the circuits of the heatingelement and the time delay switch.

2. In an oil burner, an oil delivery tube, a valve in the tube forcontrol of the discharge of oil therefrom, an electric heating elementassociated with the tube for heating the oil delivered therethrough, acircuit for the heating element, a time delay switch, a circuit for thetime delay switch, a thermostatic switch common to the heating elementcircuit and time delay switch circuit, and means under control of thetime delay switch for actuating the said control valve to open andclosed positions respectively, at predetermined time intervals followingthe energizing and deenergizing of the heating element by the actions ofthe thermostatic switch.

3. In an oil burner, an oil delivery tube equipped at its discharge endwith a control valve, a solenoid operatively connected with the valveand adapted, upon being energized, to open the valve and whende-energized, to close it, a circuit for the'solenoid, an electricalelement for heating the oil in the delivery tube, a circuit for the saidelement including a cut-out switch, a time delay switch controlling theenergization and deenergization of the solenoid circuit, a circuit forthe time delay switch, a thermostatic switch operable to control boththe heating element and time delay switch circuits and a thermostaticcontrol for said cut-out switch operable under influence of temperaturesof oil in the tube.

4. In an oil burner, an oil delivery tube equipped atits discharge endwith a control valve, a solenoid operatively connected with and adapted,upon being energized, to open the valve, a circuit for the solenoid, anelectrical element for heating the oil in the delivery tube, a circuitfor said element, a time delay switch, a circuit for the time delayswitch, a thermostatic switch for the Joint control of the circuit ofthe heating element and or the time delay switch; said time delay switchbeing operable for effecting a delayed energization and delayedde-energization of the solenoid circuit, and a temperature responsivemeans associated with the delivery tube and oil contained therein foropening the heating element circuit independently of the action of thethermostatic switch.

5. In an oil burner, a tube for delivery of oil into a combustionchamber, an atomizing nozzle at the delivery end 01' said tube, acontrol valve in the tube adjacent the nozzle, a solenoid havingoperative connection with the valve to move it between open and closedpositions, a circuit for the solenoid, an electrical element for heatingoil in the tube, a circuit for the element, a timedelay switch forcontrol of the solenoid circuit, a circuit for the time delay switch, athermostatic switch operable to control the circuits for the heatingelement and time delay switch; saidtime delay switch being arranged tocontrol the solenoid-circuit for opening and closing the valve atpredetermined time intervals after the energize.- tion andde-energization or the heating element by the action or the thermostaticswitch, and a temperature responsive element associated with the tubeand operable in accordance with temperature of the oil therein forcontrolling the heating element circuit independently of other circuitswhile the control valve is open.

6. In an oil burner, the combination with an air blast tube and meansfor delivering a blast of air therethrough into a combustion chamber,01' an oil delivery tube equipped at one end for delivering oiltherefrom in an atomized condition into the air from the blast tube, toform a combustiblemixture, a valve in the oil delivery tube at itsdischarge end, a heating circuit for the oil tube, a pump for deliveringoil under pressure into the tube, an electric motor for operating thepump, a motor circuit, a solenoid tor actuating the valve, a circuit forthe solenoid, a time delay switch operable to control the solenoidcircuit, a thermostatic swimh for control of the time delay switchcircuit and the heating circuit, and means under control of the timedelay switch to open the motor circuit.

7. In an oil burner, an air blast tube, a fan operable to supply airunder pressure to the tube for discharge into a combustion chamber, anoil delivery tube disposed within the air blast tube and equipped at itsdischarge end with means for discharge of oil from the tube in anatomized condition for mixture with the delivered air, a control valvein the tube adjacent the atomizing means, a pump operable to supply oilunder pressure to the oil delivery tube, an element for heating oil inthe tube, a circuit for the heating element a motor for operating thefan and pump an electric circuit for the motor, a solenoid for ment, atime delay switch, a circuit therefor, a-

thermostatic switch for control of the circuit of the time delay switchand heating element, and a relay operated by the time delay switch, andcontrolling the motor and solenoid circuits.

8. In an oil burner, an electric power circuit, an oil delivery tube, avalve for controlling the discharge of oil therefrom to a combustionchamber, electrically operated mechanism for actuating the valve, aheating element associated with the tube, for heating the oil therein, atime delay switch for control of the valve actuating mechanism, acontrol switch controlling the energization of the heating element andtime delay switch from the power circuit, an electrically operable pumpfor delivery of oil to the chamber, a second power circuit for saidpump, and a switch in the latter circuit operable under control or thetime delay switch to delay the de-energization of the pump for apredetermined interval after the heating means has been de-energized bythe opening of the said control switch.

9. In an oil burner of the character described, an oil delivery passage,an atomizing nozzle at the discharge end of the passage, a control valveadjacent the nozzle, electrically energized means for actuating thevalve, a source of electrical power, an electrical heating element forthe passage, a time delay switch for controlling the valve actuatingmeans for the opening and closing action of the valve in time delay tothe energizing and de-energizing of said switch, and a thermostaticcontrol switch and means electrically connecting said heating elementand said time delay switch to the power circuit through the saidthermostatic control switch.

JAMES R. HAWLEY.

